Compound (A) represented by the following formula or a pharmacologically acceptable salt thereof, or a hydrate thereof is a compound that exhibits an FXa inhibitory effect, as disclosed in Patent Literatures 1 to 3, and is useful as preventive and/or therapeutic drugs for thrombotic and/or embolic diseases.

A compound (1), an optically active diamine derivative, described in the scheme shown below is known as an intermediate for the production of compound (A) as an FXa inhibitor or a pharmacologically acceptable salt thereof, or a hydrate thereof. The pamphlet of International Publication No. WO 2007/032498 (JP 2007-106759) discloses a process for producing compound (1), comprising adding a compound (3) to an excessive amount of a tertiary amine to neutralize the salt and then adding a compound (2) to the mixture [Scheme A].
wherein Boc represents a tert-butoxycarbonyl group.